Base emitter voltage and collector current

  1. Does decrease in value of base-emitter voltage decreases collector current..??
    As I studied that decrease in base-emitter voltage of some part of signal to lesser ammplification of that part due to smaller current..but how base emitter voltage is leading to less collector current..
    because if base-emitter voltage decrease , base current increase which further increase collector current..
     
  2. jcsd
  3. NascentOxygen

    Staff: Mentor

    Yes.

    If VBE decreases, base current decreases. It's a p-n junction, so the characteristic is that of a p-n junction diode. If the forward voltage increases, the forward current increases.
     
  4. But base-emitter voltage is a barrier voltage.. so if it decreases , base current should increase..!!!
     
  5. dlgoff

    dlgoff 3,133
    Science Advisor
    Gold Member
    2014 Award

  6. But is'nt there any logic behind it...??
    because if we see this equ.
    Ib=Vb/Rb - Vbe/Rb
    so from this equ. it can be seen that if Vbe increase base current decrease..!!!
     
  7. jim hardy

    jim hardy 5,127
    Science Advisor
    Gold Member
    2014 Award

    have you ever run across the formula for current through a junction,
    I=eqv/kt
    where v would be your Vbe ?
    That's what dlgoff's graph is showing you.


    that involves not only Vbe but an external Vb and an external Rb.

    Your original question
    did not involve either.

    It is important to be rigorous in your thinking. Focus on the junction, after you've figured it out then add the external components.

    Base current and collector current are related by the transistor's Beta,
    which itself is a function of collector current.........
     
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